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temperature sensor.md

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Note

This is an attempt at formatting what we found as documentation for the temparature sensor

Product parameters:

Working voltage: DC4-30V (the highest should not exceed 33V)

Maximum power: 0.2W

Working temperature: temperature -20℃+60℃, humidity 0%RH-100%RH

Control accuracy: temperature ±0.3℃(25℃), humidity ±3%RH(25℃)

Output interface: RS485 communication (standard MODBUS protocol and custom common protocol), see protocol description for details

Device address: 1-247 can be set, the default is 1 Baud rate: default 9600 (users can set by themselves), 8 data, 1 stop, no parity Size: 60 _ 30 _ 18

MODBUS protocol

Function code used by the product:
0x03: Read holding register
0x04: Read input register
0x06: Write a single holding register
0x10: write multiple holding registers
Register type Register address Data content Number of bytes
Input register 0x0001 Temperature value 2
0x0002 Humidity value 2
Holding register 0x0101 Device address (1~247) 2
0x0102 Baud rate 0:9600 1:14400 2:19200 2
0x0103 Temperature correction value (/10) -10.0~10.0 2
0x0104 Humidity correction value (/10) -10.0~10.0 2

Modbus communication format:

Host sends data frame:
Slave address function code Register address High byte Register address Low byte Number of registers High byte Number of registers Low byte CRC High byte CRC Low byte

The slave responds to the data frame:
Slave address Response function code Number of bytes Register 1 data High byte Register 1 data Low byte Register N data High byte Register N data Low byte CRC High byte CRC Low byte

MODBUS command frame

The host reads the temperature command frame (0x04):

Slave address function code Register address High byte Register address Low byte Number of registers High byte Number of registers Low byte CRC High byte CRC Low byte
0x01 0x04 0x00 0x01 0x00 0x01 0x60 0x0a

The slave responds to the data frame:

Slave address function code Number of bytes temperature High byte temperature Low byte CRC High byte CRC Low byte
0x01 0x04 0x02 0x01 0x31 0x79 0x74

Temperature value = 0x131, converted to decimal 305, actual temperature value = 305/10 = 30.5℃

Note

The temperature is a signed hexadecimal number, temperature value=0xFF33, converted to decimal -205, actual temperature = -20.5℃;

The host reads the humidity command frame (0x04):

Slave address function code Register address High byte Register address Low byte Number of registers High byte Number of registers Low byte CRC High byte CRC Low byte
0x01 0x04 0x00 0x02 0x00 0x01 0xC1 0xCA

The slave responds to the data frame:

Slave address function code Number of bytes humidity High byte humidity Low byte CRC High byte CRC Low byte
0x01 0x04 0x02 0x02 0x22 0xD1 0xBA

Humidity value=0x222, converted to decimal 546, actual humidity value=546 / 10 = 54.6%;

Continuously read the temperature and humidity command frame (0x04):

Note

I believe the original author meant continuously as in "multiple" and not continuously as in "over time"

Slave address function code Register address High byte Register address Low byte Number of registers High byte Number of registers Low byte CRC High byte CRC Low byte
0x01 0x04 0x00 0x01 0x00 0x02 0x20 0x0B

The slave responds to the data frame:

Slave address function code Number of bytes temperature High byte temperature Low byte humidity High byte humidity Low byte CRC High byte CRC Low byte
0x01 0x04 0x04 0x01 0x31 0x02 0x22 0x2A 0xCE

Read the content of the holding register (0x03):

Take reading the slave address as an example:

Slave address function code Register address High byte Register address Low byte Number of registers High byte Number of registers Low byte CRC High byte CRC Low byte
0x01 0x03 0x01 0x01 0x00 0x01 0xD4 0x0F

Slave response frame:

Slave address function code Number of bytes Slave address High byte Slave address Low byte CRC High byte CRC Low byte
0x01 0x03 0x02 0x00 0x01 0x30 0x18

Modify the content of the holding register (0x06):

Take the modification of the slave address as an example:

Slave address function code Register address High byte Register address Low byte Register value High byte Register value Low byte CRC High byte CRC Low byte
0x01 0x06 0x01 0x01 0x00 0x08 0xD4 0x0F

Modify slave address: 0x08 = 8

Slave response frame (same as sending):

Slave address function code Register address High byte Register address Low byte Register value High byte Register value Low byte CRC High byte CRC Low byte
0x01 0x06 0x01 0x01 0x00 0x08 0xD4 0x0F

Continuously modify the holding register (0x10):

Slave address function code initial address High byte initial address Low byte Number of registers High byte Number of registers Low byte Number of bytes Register 1 high byte Register 1 low byte Register 2 high byte Register 2 low byte CRC High byte CRC Low byte
0x01 0x06 0x01 0x01 0x00 0x02 0x04 0x00 0x20 0x25 0x80 0x25 0x09

Modify slave address: 0x20 = 32 Baud rate: 0x2580 = 9600

Slave response frame:

Slave address function code Register address High byte Register address Low byte Number of registers High byte Number of registers Low byte CRC High byte CRC Low byte
0x01 0x06 0x00 0x11 0x00 0x04 0xD4 0x0F

Normal version agreement

The default baud rate is 9600 (users can set by themselves), 8 bits of data, 1 bit of stop, no parity RS485 communication

Serial command Description
READ Trigger a temperature and humidity report (27.4℃, 67.7% temperature 27.4℃ humidity 67.7%)
AUTO Start the automatic temperature and humidity report function (Same as above)
STOP Stop the automatic reporting of temperature and humidity
BR:XXXX Set the baud rate 9600~19200 (BR: 9600 baud rate is 9600)
TC:XX.X Set temperature calibration (-10.0~10.0) (TC:02.0 temperature correction value is 2.0℃)
HC:XX.X Set humidity calibration (-10.0~10.0) (HC:-05.1 Humidity correction value is -5.1%)
HZ:XXX Set the temperature and humidity report rate (0.5,1,2,5,10) (HZ: 2 automatic reporting rate 2Hz)
PARAM Read current system settings，

PARAM instruction: TC:0.0,HC:0.0,BR:9600,HZ:1 -> Temperature correction value 0.0 Humidity correction value 0.0 Baud rate 9600 Report rate 1Hz SLAVE_ADD:1 ->MODBUS slave address 0x01